TSS463 ATMEL Corporation, TSS463 Datasheet - Page 8

• Manufacturer Part Number: TSS463
• Description: VAN Data Link Controller with Serial Interface
• Manufacturer: ATMEL Corporation

Intel SPI Mode
Figure 5. Typical Application With the 8051 UART in Mode 0
8
TSS463B
Remaining pins
RESET (1)
PORT X.z
PORT X.y
XTAL1
TXD
RXD
IRQ
When the master (CPU) conducts a read, it sends an address byte, a control byte and
dummy characters (’0xFF’for instance) on its MOSI line. In the case of a VAN messages
RAM read (VAN frame received), the first data byte sent back by the TSS463B on its
MISO pin is the data length so the master knows how many dummy characters it must
send to read the VAN frame properly. When the TSS463B responds back with data, it
will not take care of the MOSI line.
The master must activate and desactivate SS between each data frame.
Synchronization bytes must be monitored carefully. For instance, if ’0xAA’and ’0x55’are
not monitored correctly, then the previous transmission may be incorrect too.
A control byte containing ’0x00’or ’0xFF’is forbidden except during an ’Initialization
Sequence ’.
The Intel SPI mode is the second type of interface. As mentioned before, the TSS463B
enters this mode if the Initialization Sequence contains (first two bytes received) ’0xFF,
0xFF’.
This mode is fully compatible to the Intel UART serial interface programmed in mode 0
only. It is the same as Motorola SPI mode (same CPOL and CPHA) but with inverted
communication sense (LSB first and MSB last). The protocol is also the same.
However, from the master point of view (host microcontroller), the hardware is different.
Figure 5 shows how to connect the TSS463B and Intel type microcontroller.
Note:
General I/O
1. The RESET pin can either be connected to GND through a 1 µF capacitor, or to the
microcontroller RESET pin, or unconnected (inactive with internal pull-up).
C1
C2
optional
(if needed)
100k
TEST/VSS
INT
VDD
XTAL1
CKOUT
XTAL2
MISO
SS
1
2
3
4
5
6
7
8
15
16
14
13
12
11
10
9
MOSI
SCLK
RESET (1)
RxD1
GND
TXD
RxD0
RxD2
VAN Bus
4102E–AUTO–12/04